Tel(omere) Me About It: Can Your Telomeres Tell You How Well You Are Aging?

by Ana Driscoll

Everyone wants to age well. Our fascination with maintaining our youthfulness has persisted since ancient times, when the Greeks used snail slime as an anti-aging treatment. Fortunately, we don’t use that anymore – but still, today’s anti-aging industry capitalizes on our obsession with technology and health. Most recently, you may have seen advertisements on national television for at-home tests that promise to show how well you are aging by measuring telomere length. It sounds like something straight out of science fiction, but in the near future you may make a decision about whether to buy such a test. Are they worth it? What are telomeres anyway? To find out, we must return to the source of our genetic code: DNA.

Every single cell in our bodies contains DNA. When our cells reproduce, our DNA must also be replicated so that each new cell contains a complete copy of our genetic material. The double-stranded nature of DNA allows it to be “unzipped” during the replication process. Both strands of the original molecule then serve as a template to which new bases are added and create two new double-stranded molecules. It sounds fairly straightforward, right? So what’s the problem?

Due to the direction in which new bases are added during DNA replication, one end of each parent strand is left unfinished -- no new bases are added, creating a single-stranded overhang that quickly gets degraded. This means that our DNA becomes slightly shorter every time our cells divide. Fortunately, there are no genes at the ends of our DNA, just repeating sequences that do not code for anything at all. These sequences are called telomeres.

As we get older, our cells divide more and more, and our telomeres get shorter and shorter. Eventually, cells either stop reproducing or die when their telomeres reach a certain critical length. Therefore, aging is associated with decreased telomere length. Telomere lengths that are shorter than average for a given age group are associated with age-related diseases, such as high blood pressure and coronary artery disease.

Many factors may affect telomere length, so the exact combination of genetic, socioeconomic and environmental influences is unclear. We have, however, found some consistencies. For instance, smokers, people who are obese, and those under high levels of stress all tend to have shorter telomeres. This proposes that positive dietary choices could be associated with longer telomeres. Outside lifestyle choices, it is thought that heritability is responsible for between 44 percent and 80 percent of variations in telomere length. Other potential influences on telomere length are race and mental health. Major depressive disorder and other mood disorders may be associated with shorter telomere length, and a recent study found that African Americans have shorter telomeres than whites. So, though telomeres don’t tell the whole story, they can serve as useful biomarkers, or indicators, for age-related degeneration.

In the past few years, some companies have capitalized on this, creating biomarker tests to indicate how well you are aging. By comparing your average telomere length to that of others your same age and gender, these tests give you an idea about whether your “biological age” matches up with your real age. Usually the tests are done in a lab, and although different companies use slightly different methods, generally DNA is extracted from a sample of blood or saliva and then cut into pieces using specialized enzymes that do not cut sequences found in telomeres. Telomeres are then isolated based on fragment length, and the samples are compared to population data on telomere length. Your resulting “biological age” is usually given as a percentile. The cost of a telomere test varies, with two major companies charging $89 and $150 respectively for an individual test. So far, the results have been proven to be accurate.

For some, telomere testing may provide motivation to start living a healthy lifestyle or – in extreme cases – suggest an underlying genetic condition. We already know that eating well, exercising and taking care of our mental health has a positive impact on our overall well-being, but a telomere test may give the push needed to start that healthy lifestyle. Since its commercialization, telomere testing has become an affordable and attainable and way to measure your aging against the rest of the world. Perhaps in the future, it will be up to your telomeres to decide.